{"id":280344,"date":"2023-04-19T13:29:11","date_gmt":"2023-04-19T13:29:11","guid":{"rendered":"\/forum\/forums\/topic\/bolt-pretension-strange-behaviour\/"},"modified":"2023-04-19T13:29:11","modified_gmt":"2023-04-19T13:29:11","slug":"bolt-pretension-strange-behaviour","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/bolt-pretension-strange-behaviour\/","title":{"rendered":"Bolt Pretension &#8211; Strange Behaviour"},"content":{"rendered":"<p>Hi,<\/p>\n<p>I have a pipe model with three flanged bolted connections:<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/04\/19-04-2023-1681909809-Screenshot Geometry.png\" alt=\"\"><\/p>\n<p>I have defined two load steps for which the first one is used to pretension the bolts (only by a force of 100 N). The pretensioning is then locked in the second load step. I have used local coordinate systems for pretensioning each of the bolted connections such that the pretension cutting plane is in the middle between each pair of flanges. This ensures that the pretensioning is not applied where bonded contact is defined. An example showing two of the pretensioned flanged connections:<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/04\/19-04-2023-1681910065-Pretension.png\" alt=\"\"><\/p>\n<p>When running the analysis two of the connections seem to be unaffected by the pretensioning while the third appears to be stretched instead of pulled together:<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/04\/19-04-2023-1681910566-Result.png\" alt=\"\"><\/p>\n<p>What can be the reason for this behaviour? I have tried redefining the local coordinate systems and going over the contact defininitions but with no luck.<\/p>\n<p>I am attaching a .wbpz-file in case anyone would like to investigate the model: https:\/\/drive.google.com\/drive\/folders\/1O99qyQ23OP6P2XWijXUIqTOWGPOHHOGF?usp=sharing<\/p>\n<p>(The loads in load step 2 can be disregarded as they are not part of the problem).<\/p>\n<p>Thanks!<\/p>\n","protected":false},"template":"","class_list":["post-280344","topic","type-topic","status-closed","hentry","topic-tag-bolt-pretension","topic-tag-bolt-pretensioning-1","topic-tag-coordinate-system","topic-tag-mechanical","topic-tag-pretension-1"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["208645","282727","200"],"_bbp_author_ip":["23.44.170.21"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["1800"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["280344"],"_bbp_forum_id":["27796"],"_bbp_engagement":["200","208645","282727"],"_bbp_voice_count":["3"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["281094"],"_bbp_last_active_id":["281094"],"_bbp_last_active_time":["2023-04-25 11:16:51"]},"test":"tortjubystol-no"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/280344","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/280344\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=280344"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}